Linear expansion apparatus



Feb. 26, 1935. P. E. KLOPSTEG LINEAR EXPANSION APPARATUS Filed Se t. 27, 1929 LIZ I111 10 companying drawing; in which:

30.. represented by a pointer 12 carried by and fixed g o y Surrounds that l 01 the 1001}; which 30 '55" and is integral with the .f r-ontnbearing support 18., for every millimeterof ccntractionorexpansion 5 5 Patented Feb. 26,1935 1,992,219

i "UNITED, PATENT oFrlcEipi f ,11; lawma I LINEAR EXPANSION APPARATUS Paul E; Klo'psteg; Chicago, .Ill., assignor to Cen- V tral Scientific Company," a corporation of Y .j u v Application september 27,1929, seseme aem 1 11 Claims. H (cuss-12);

This invention relates to' linear expansion'apandscale 22 is appropriately secured to support. paratus, and among other objects, aims to pro- 21. '"I'lifegraduations-on the scale are arbitrary vide apparatus bywhichthe phenomenaof therin character though preferably-equally spaced; mal expansion and contraction may be studied". they and the indicating numerals are made sufli 5. and visiblydemonstrated and coeflicientsof exciently large 'to be visiblefrom any point of a 5 pansion may be easily determined. 1: largedemonstr'ation room. *The pointerextends The nature of the invention maybe readily" behindlthe'sc'al''and f extremity is bentdOWn understood by reference to one construction emwardly from above as at 23 to overliethe graduabodying the invention and illustrated in the actionsicn the' scale. A hook 24 carried by the inner I jspring15 prov'idesmeans for connecting one end Fig.1 is a side elevation of the apparatus? of p m 2 1 in ic i m p Fig. '2 is a: front elevation; and e j ing apparatus. Thejothe'r end of' the specimen Fig. 3 is a detail section 'taken on the line 33 is advantageously conn cted o an adjusting c w of Fig. 2 of the apparatus of the mechanism for 25 byappropriate means represented by thehook V effecting a multiplication of the actual expan 26. ""lheadjusting screw'is mounted'in apedestal 15-- sion of a specimen. e i w a 27 whichlike'the pointer pedestal lfi isbolted or 'I'li'eillustrative' apparatus hasbeen designed to otherwiseappropriately secured to theiapparatus effect thermal expansion of specimens of .wire and basej28. The screw is adjusted in or out 'by a the like by means of an electric current passed: humb nut 29 a d any desired j t e ay be 0. through the specimen. e l maintained bya setscrew 30,'which also servesto The linear expansion or contraction of the specp e i e dj t n S ewimen is transmitted to mechanism which multi- For the pu o electrically la g t plies and visibly indicates the degreeof'expanp a s fiand 7 from eachother and from sion or contraction. The specimen is here shown the base, the base -1 1 this as being a e of 2s in the form of a wire 10 of any appropriatemametal, n u t g wa shims 3 d terial such as iron, brass, nickelsilver or the like, 32 a e placed 011 pp ces Of the base whose ends have been twisted intot'loops 11' to 'Y fi Y S p e bot m faces providemeans for connection with the apparatus. of the p e s d e Connecting b01 8 f om the l v The multiplying and indicating'mechanism' is; base. A sleeve 33 of insulating material advantoe shaft "13; The specimen-is so connectedyto passes u h t 'b se. V e e e shaft 13 that it rotates the shaft'aperipheraldis Electric u n is passed u the speci tance equal to the aggregate expansion. or eonmen by electlic Wires ted o binding PQ traction of thespecimen. Inthe present casesuch M 3 onethei respective p sQw 35: connection is effectedby a flexible element 14 this instance also'serve as connecting bolts, thus 35 such as a stout cord or the likewhich is wrapped placing theispecimen inseries with'anappropria'te three or moretimes around .the shaftlto-prolp l", 511011253 SiXWOIt f yv ide adequate frictional engagement ther with After'a spe'cimenhas been connected to the and is maintained in taut condition by tensioning h0O 2633118 111113329 is u d b R t 40.- means in the form of flat sprin s ls connected pla e s m s ht t n in th w r h s m 40 adjacent the. respectiveends of the-element 14; er may be adjusted tozero or any desired pointon Thesprings are bolted or otherwise appropriatethe scale ibymomentarily pressing together the 1y secured at their opposite ends to theQpedestal two springs 15 to relieve the frictional grip of 16. Thefshaft 13 issupported in bearings which elementl upon shaft113. The scale ".(which, as

451 minimizefrlction. 'Such bearingsaresimilar'to stated above; jmay beearbitrary in character) those employed in delicate measuring apparatus may be calibrated relative to the actualexpanandcomprise adjustable screw pins 17 carried in sion or contraction of the-specimen by :observing the bearing supports '18gand 19 of the pointer the displacementof the pointer made byoncnor. pedestal 16 and intothe recessed extremitieslof morerotations of the adjusting nut 29. To simpli- I 5;); which the :pointed endscf the shaft 13 project. fy such calibration the adjusting screw 25 isade 59 The bearing is adjustedby screws 17 and such ade vantageously designed with a pitch of one milliei justment is maintained bylocknutszn. 1- metene Thus thedisplacement; of. the pointer. 'Ihezpedestal .16. is provided. with a. scale su'pon the scale produced by a single rotation of screw port. 21 which in this instance extends vertically 29 indicates the displacement which wouldoccur of the specimen. Having calibrated the scale in this manner the actual expansion or contraction of the specimen may be readily determined.

For convenience in forming the specimen wires of standard length, it is desirable to provide a pair of pins 35 on the base adjacent the pedestals spaced apart a convenient distance within the range of separation of the books 24, 26,.as shown in Fig; 2. ,It is obviousthat these pins may be used as a sort of template to form the loops '1 on the specimen wire. 7

Among other uses, the apparatus alfords an excellent means for studying the'behavior, of a specimen throughout, av temperature range. The magnification of the change in length effected by the present apparatusis about'one to two hundred. Hence, the movement of the pointer on the scale gives a striking visual demonstration of the changes in length (though microscopic in character) actually taking place under the influence of changes in temperature in'the specimen.

To determine the coefficient of linear expansion of a specimen it is necessary to determine the temperature range, in additionto the length of the specimen .and the change in length under expansion or'contractiom The initial temperature may advantageously be takenas room temperature. sAnother point in the range oftemperatures may be determined by utilization of the known melting temperature of another material. For example,-a narrow strip, of pure tinfoil 37 (one-half to one millimeterin width) may be hung over the specimen (the specimen being carefully cleaned at this point), and a small weight 38 vofone or two grams attached to this strip;

When} thesmall weight is heard to drop upon the initial and final pointer positions by the 'pre-.'

viously determined calibration; t'is the final temperature, in this case 232 C.; to'the initial or room temperature; and L the length of the speclmen. 7,

The. apparatus may also advantageously be used to demonstrate certain phenonena taking place during: temperature changes suchv as the decalescence and recalescence points of steel. When the temperature of a steel specimenis raised in theapparatus thepointer will indicate expansionup to the decalescence point at which time (because of the absorption of heat during molecular changes occurringin the'wire) expansionmomentarily ceases and in fact a slight contraction may be indicated. .Upon cooling of the wire from a. temperature above'thedecalescence; point, the pointer indicates contraction until the recalescence point isreached, at which time owing totherelease of heat (upon a restoration of" the initial molecular condition in the specimen), contraction momentarily ceases and in fact some slight expansion may occur before contraction is resumed. Both of the foregoing.

phenomena are strikingly indicated byth'e move ment of the pointer, and an appreciation of what takesplace in thewire (though microscopic in character) may be had from an observation of the action of thepointer. r

The apparatus may also be employed to demonstrate the phenomena of a hot wire ammeter. For such use the scale is initially calibrated by connecting an appropriate wire specimen such as brass or-nickel silver in series with an ammeter.

When so calibrated the apparatus may be used.

for directly measurng either direct or alternating current of any frequency;

Obviously the invention is details of the illustrative construction since'these not limited to the may be variously "modified. Moreover, it is not indispensable that all features'of the invention be used conjointly, since various features may be advantageously employed in different combinations and sub-combinations.

I- claim as my invention: LLaboratory expansion apparatus of the character described comprising in combination,

means for supporting a flexible specimenof ma- ,terial whichexpands when heated, means for changing the temperature of the specimen 'to cause it to expand or contract, a shaft arranged.

to be connected with and rotatedby the expansionrand contraction of the specimen, means for multiplying the effect of said rotation to render, themovement produced visible to the eye, and a measuring device connected to the specimen for calibrating said multiplying means. '2. Laboratory expansion apparatus of the character described comprising in combination,- means for supporting a flexible specimen of material which expands when heated, means for 1 changing the temperature of the specimen to cause it to expand or contract, a shaft arranged to be connected with and rotated by the expansion and contractionof the-specimen, means for multiplying the effect of said rotationto render the movement produced visible to the eye,'an,d a.

screw of known pitch connectedwiththespeci men for moving said wire a known distance to calibrate said multiplying means.

, 3. Laboratory expansion apparatus of the character described comprising in combination, means for supporting a specimen ofjmaterial which expands 'whenheated, means for changing the temperature, of the specimento cause it to expand or contract, a shaft of relatively small diameter having a flexible cord wrappedaround said shaft andprovided with means for connec -tion with the specimen, spring means formaintaining said cord taut to create adequate friction against said shaft, and a device controlled by theshaft for registering the expansive or contractive movements of the specimen, said spring means being constructed and arranged to permit the release of said friction so that the registering may be adjusted to any desired position.

4. Laboratory apparatus for linear expansion and contraction comprising in combination, ".a

fixed and am'ovable specimensupport each'provided with means for receiving a specimen adapted to be heated byjthe passageof an elece tric ourrent through it and to expand whenjso heated, ashaft of relatively small diameter having a multiplying pointer connected'thereto," a scale associated with saidlpointer and provided withgraduations of'a'size visible froma sub. stantial distance, a flexible cord wrapped around said shaft andfconnected t o saidimovable support, releasable means for maintaining the friction' of. said cordon said shaft, and "electrical 5. Laboratory apparatus for linear expansion and contraction comprising in combination a fixed and a movable specimen support each provided with means. for receiving a specimen adapted. to be heated by. the passage of an electric current through it and toexpand when so ing a known linearmovement of said specimen for calibrating said scale, and electrical'terminals connected with said supports for passing a heating current through said specimen.

6. In apparatus for studying the linear expansion of a specimen of heat-expansible material provided in a form adapted to beheated by conduction of anelectric current, a base, an adjustable support for th'especimen mounted adjacent one end of the base, a second support for the specimen mounted adjacent the other end of the base and electrically insulated from the first support, means, for passing an'electric current through the specimen, and means associated with the second support for 'yisibly indicating the expansion or contraction of the specimen.-

7. In apparatus for studying the linear expension of a specimen of' heat-expansible mate- I rial provided ina form adapted to be heated by conduction ofanelectric current, an elongated base, specimen supports mounted adjacent the two ends of the base and electrically insulated therefrom, means for passing an electric cur rent throughthe specimen,fand multiplying means associated with one I of the supports for visibly indicating change in the linear dimension .of the specimen. 1 v

8. The method of demonstrating the linear.

expansion of a specimen of material adapted to expand when heated which includes taking a the substance may be observed.

be heatedby conducting an electric current, supspecimen of knownlength in a form adapted to porting thespecim'en'between a relatively fixed and a relatively movable point, hanging on the specimen a small mass of substance of known melting point lower than that of the specimen and suspending a weight from said substance,

passing an electric current'through the? speciheated, a shaft of relatively small diameter'having a multiplying pointer connected thereto, a scale associated with said pointer and provided men of sufiicientstrength to melt the substance by heat conducted from the specimen, whereby the increase in length of the specimen at the instant the weight falls due to the melting of 9. The method of demonstrating the linear expansion of a specimen of material-adapted to expandw'nen heated which includes takingza specimen of known length in a form adapted to be heated by'conducting an electric current, supporting the specimen between a relatively fixed and a relatively movable point, hanging on the specimen a small mass of substance of known melting point lower than that of andsuspending. a weight from said substance, passing an electric current through the specimen of suflicient strength to melt the substance by heat conducted from the specimen, magnifying the change in position of I, the movable point so that it is readily visible to the eye, whereby the increase in length of the specimen at the instant the weight falls due to the melting of the substance may be observed.

10. In apparatus of the class described, a base, a pair of pedestals mounted on the base adapted to support under tension and in horizontal position a flexible specimen adapted to expand when heated, a calibrating device associated with one of the pedestals and a linear expansion indicating device associated with the other pedestal.

mounted on the base and adapted to support under tension between them a flexible specimen adapted to expand when heated, and means associated with one of the pedestals for visibly indicating a change in the length of the specimen.

PAUL KLOPSTEG.

the 1 specimen 

